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Prepared by Cindy Safrit and Daphne Cartner
Dam Failures Do Occur
No one knows precisely how many dams have failed in the US from January 1, 2005 through June 2013
All State Dam Safety programs have documented failures
From this the Association of State Dam Safety Officials
173 dam failures and 587 “incidents”Reported
“incidents” being episodes that without intervention, would likely have resulted in dam failure
Feb 22, 1976: New-Found Creek Dam Buncombe Co. (near Canton, NC)
Family of 4 Died
Sept. 15, 1989: Evans/Lockwood Dams Fayetteville, NC (due to overtopping)
2 Children died
Sept. 1999: 40 failures in NC due to Hurricane Floyd
May 26, 2003: Hope Mills Dam NC estimated $2.1 million in damages, 1600 people evacuated & estimated $6 million to rebuild (due to stuck dam gate & heavy rain)
May 27, 2003: Lake Upchurch and McLaughlin Lake dams NC 4 additional dams damaged, another 16 overtopped
April 25, 2011: Carolina Lake Dam Moore County (breach along principal spillway)
1. It identifies potential emergency conditions that can occur Landowner should be aware of prominent types of failure and their telltale signs (3 general categories of failure: Overtopping, Seepage & Structure)
1. Defines responsibilities and procedures for each potential condition for all 3 levels of emergency 3 Emergency Levels (Green, Yellow & Red) will be covered later
2. Provides Contacts and numbers for the 3 emergency levels
3. Provides locally available resources with phone numbers for Equipment, Materials & Labor should the need arise
2 Templates
1. NC DSWC EAP document : 12 Pages
This should be used for Low or Intermediate Hazard Dams This EAP is a simplified version of the NCDENR EAP. It can be found on the divisions website/Technical Services/Planning and design tools Under “Pond Design” http://www.ncagr.gov/SWC/tech/onlinedesigntools.html
2. NC DENR LQ EPA document: 68 Pages
This should be used for High Hazard DamsThis document can be located at:http://portal.ncdenr.org/web/lr/dams Under “Planning for a Dam Emergency”
A- Low Hazard Dam
B- Intermediate Hazard Dam
C- High Hazard Dam
3 Hazard Classes As Defined by
NC DEMLR Dam Safety Section
DEMLR Hazard forms can be found on the Division Web site Under Pond planning and Design http://www.ncagr.gov/SWC/tech/onlinedesigntools.html
A - Low Dams located where failure may damage uninhabited low value non-residential buildings, agricultural land, orlow volume roads.
Hazard Classification Quantitative Guidelines
Interruption of road service Less than 25 vehicles/day
Low Road Volume Less than 25 vehicles/day
Economic Damage Less than $30,000
B –Intermediate Dams located where failure may damage highways or secondary railroads, cause interruption of use or service of public utilities, cause minor damage to isolated homes, or cause minor damage to commercialand industrial buildings. Damage to these structures will be consideredminor only when they are located in back water areas not subjected to thedirect path of the breach flood wave; and they will experience no morethan 1.5 feet of flood rise due to breaching above the lowest groundelevation adjacent to the outside foundation walls or no more than 1.5feet of flood rise due to breaching above the lowest floor elevation of thestructure, the lower of the two elevations governing. All other damagepotential will be considered serious.
Hazard Classification Quantitative Guidelines
Damage to HighwaysInterruption of Service
25 to less than 250 vehicles/day
Economic damage $30,000 to less than $200,000
C - High Dams located where failure will likely cause loss of life or serious damage to homes, industrial and commercial buildings, important public utilities, primary highways, or major railroads.
Hazard Classification Quantitative guidelines
Loss of Life Probable loss of 1 or more human lives
Economic Damage More than $200,000
Probable loss of human life due to breached roadway or bridge on or below dam
250 or more vehicles per day
Although it may seem daunting at first, if broken down into its 4 major steps
IT’S NOT SO BAD!!!!
Step 1: Event Detection and Level Determination
Step 2: Notification and Communication
Step 3: Expected Actions
Step 4: Termination and Follow up
Step 1 - Event Detection and Level Determination During the initial step, an unusual event or emergency event is detected at the dam and
classified by the (EAP Coordinator or designee) into one of the following event levels:
Event Level 1, RED: Urgent!! Emergency Event, Dam failure imminent or is in
progress
Event Level 2, YELLOW: Emergency Event, potential dam failure situation, rapidly
developing
Event Level 3, GREEN: Unusual Event, slowly developing
Emergency level definitions and Appendix B can be used to help the EAP Coordinator or
designee determine which of the above event levels is applicable.
Levels are numbered and color coded to prevent confusionBELIEVE IT OR NOT
IT DOES HELP
First things First Who is the EAP Coordinator or Designee
Who is the key decision maker responsible for initiating an EAP?
A: Soil and Water Conservation
B: Local Emergency Management
C: The governor
D: The dam owner
THE OWNER MAY DESIGNATE RESPONSIBILITES IF THEY ARE NOT
COMFORTABLE OR UNTIL THEY BECOME COMFORTABLE MAKING THE CALLS
Event Level 1, RED:
� Urgent!!! Dam failure imminent or is in progress and cannot be prevented
� Evacuation is necessary
Examples
Spillway flowing with advancing head cutting that is threatening the control section of the auxiliary spillway.
Earthen dam is overtopping
Sinkhole is enlarging rapidly
Event Level 2: Yellow�Potential dam failure situation, rapidly developing
�Situation could lead to dam failure, but there is not an immediate threat of dam failure
� Monitoring is necessary� Evacuation may become necessary
Examples
Spillway flowing with active gully erosionReservoir level 1 foot below the top of dam (within the structural
freeboard)Cracks in the embankment with seepage
Emergency Level 3: Green
�Unusual event , slowly developing
�Situation has not yet threatened the operation or structural integrity of the dam
Examples
New seepage area (clear flow)
New crack in the embankment without seepage or sliding
Auxiliary spillway flowing with no active erosion
Event ConditionEmergency
level*
Earth spillway flow
Reservoir water surface elevation at auxiliary spillway crest or spillway is flowing
with no active erosion
3
Spillway flowing with active gully erosion 2
Spillway flow that could result in flooding of people downstream if the reservoir
level continues to rise
2
Spillway flowing with an advancing headcut that is threatening the control section 1
Spillway flow that is flooding people downstream 1
Embankment overtopping
Reservoir level is 1 foot below the top of the dam 2
Water from the reservoir is flowing over the top of the dam 1
Seepage
New seepage areas in or near the dam 3
New seepage areas with cloudy discharge or increasing flow rate 2
Seepage with discharge greater than 10 gallons per minute 1
Sinkholes
Observation of new sinkhole in reservoir area or on
embankment 2
2
Rapidly enlarging sinkhole 1
Embankment cracking
New cracks in the embankment greater than ¼-inch wide without seepage 3
Cracks in the embankment with seepage 2
APPENDIX BEVENT LEVEL DETERMINATION GUIDANCE
After the owner has determined the appropriate event Level they should make contacts
Appendix C : Level 1, RED ONLY: Residents business at riskAppendix D: Emergency Service Contacts of all 3 LevelsAppendix E: Locally Available Resources (Equipment, Labor etc…)
Just think of it as the emergency numbers you leave with a baby sitter
When we are in an emergency we can never think of who to call or their numbers
Entity
No.
Resident/business/roads
or other impacted entity
Property Address Phone No. with area
code
Distance
downstream
from dam
(mi)
X Name of entity Address/location of entity XXX-XXX-XXXX Distance from
dam
X Name of entity Address/location of entity XXX-XXX-XXXX Distance from
dam
X Name of entity Address/location of entity XXX-XXX-XXXX Distance from
dam
X Name of entity Address/location of entity XXX-XXX-XXXX Distance from
dam
APPENDIX C
Residents/Businesses/Roads/Infrastructure at Risk
A brief summary and contact information for entities within the hazard zone.
All should be notified if: Level 1, RED Emergency:
(Use additional sheets if necessary)
Agency / Organization Principal Contact AddressOffice Phone No. with
Area Code
Alternate Telephone
Numbers
Owner/Representative of Name of
DamName of owner Contact Address XXX-XXX-XXXX XXX-XXX-XXXX (H)
XXX-XXX-XXXX (C)
Local Soil and Water Conservation
District Office
Contact Name Contact Address XXX-XXX-XXXX XXX-XXX-XXXX (H)
XXX-XXX-XXXX (C)
Design Engineer Contact Name Contact Address XXX-XXX-XXXX XXX-XXX-XXXX (H)
XXX-XXX-XXXX (C)
Agency / Organization Principal Contact AddressOffice Phone No. with
Area Code
Alternate Telephone
Numbers
County Emergency Management
Director
Name of Director Contact Address XXX-XXX-XXXX XXX-XXX-XXXX (C)
APPENDIX DEmergency Service Contacts
Level 3, GREEN Unusual Event
Level 2, Yellow Emergency
In addition to contacting Agencies and Organizations for Level 3, Green Unusual Event these additional contacts shall be made IF downstream hazard exist
Agency / Organization Principal Contact AddressOffice Phone No. with
Area Code
Alternate Telephone
Numbers
XXXX County Sheriff Sheriff’s Name Contact Address XXX-XXX-XXXX XXX-XXX-XXXX (C)
Local Fire Department Contact Name Contact Address XXX-XXX-XXXX XXX-XXX-XXXX
Local Police Contact Name Contact Address XXX-XXX-XXXX XXX-XXX-XXXX
Local Highway Patrol Contact Name Contact Address XXX-XXX-XXXX XXX-XXX-XXXX
Level 1, RED Emergency:
In addition to contacting Agencies and Organizations for Level 3, GREEN
Unusual Event and Level 2, YELLOW Emergency these additional contacts
shall be made IF downstream hazards exist (Appendix C)
APPENDIX D (Cont)
After the initial notifications are made, the (EAP
Coordinator or designee) should confer with the (Design
Engineer or designee) and the local soil and water
conservation district office to develop and execute
appropriate preventative actions. During this step of the
EAP, there is a continuous process of taking actions,
assessing the status of the situations, and keeping
others informed through communication channels
established during the initial notifications. The EAP may
go through multiple event levels during Steps 2 and 3 as
the situation either improves or worsens.
Once the event has ended or been resolved,
termination and follow-up procedures should be
followed as outlined in Section 4 of this EAP. EAP
operations can only be terminated after completing
operations under Event Level 3 or 1. If Event Level 2
is declared, the operations must be designated Event
Level 3 or 1 before terminating the EAP operations.
Terminate the EAP
Hold a Follow up meeting
If necessary, Stabilize the area
Develop a repair plan if necessary
Owner’s Responsilibilities
Local Emergency Management
Responsilibilities
DETECTION
STEP 1 DECISIONMAKING
STEP 2 NOTIFICATION
STEP 3 PREVENTATIVE ACTION WARNING & EVACUATION
STEP 4TERMINATION & FOLLOW-UP
It must be undated periodically (YEARLY) to have the greatest effectiveness
What should be tested/checked/updated?
�Hazard should be checked and verified�Call all contacts to verify phone number and
contact person name�Owner verifies that contact person can find
EAP
THEN LETS LOOK AT SOME PICTURES OF
MOST COMMON FAILURES
Breach along principal spillway
Picture from Association of State Dam Officials
http://www.damsafety.org/media/Documents/Images-Animations/Dam%20Animations/Overtopping.wmv
Picture from Association of State Dam Officials
http://www.damsafety.org/media/Documents/Images-Animations/Dam%20Animations/Piping.wmv